Method of forming structures wholly of fusion deposited weld metal



Oct. 27, 1942. v HARTER 2,299,747

METHOD OF FORMING STRUCTURES WHOLLY OF FUSION DEPOSITED WELD METALOriginal Filed Aug. 10, 1938 3 Sheets-Sheet lllllllml/HIHHHIHHlllllHl/HHI Ill!!! w& 7

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METHOD OF FORMING STRUCTURES WHOLLY OF FUSION DEPOSITED WELD METALOriginal Filed Aug. 10, 1938 5 Sheets-Sheet 2 Fig. [3

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Isaac Hm 661" A if orn Oct. 27, 1942. H R 2,299,747

METHOD OF FORMING STRUCTURES WHOLLY OF FUSION DEPOSITED WELD METALOriginal Filed Aug. 10, 1958 3 Sheets-Sheet 3 INVENTOR. I saac Harte!Attorney Patented Oct. 27, 1942 METHOD OF FORMING STRUCTURES WHOLLY OFFUSION DEPOSITED WELD METAL Isaac Hatter, NewlYork, N. Y., assignor toThe Babcock & Wilcox Company, Newark, N. .L, a corporation of New JerseyOriginal application August 10, 1938, Serial No. 224,022. Divided andthis application April 9, 1941,,Serial No. 387,584

4 Claims.

This invention has reference to an article and the method of making thesame wholly from metal deposited by a fusion process.

The present invention contemplates an article consisting of fusiondeposited metal, produced in such manner as to provide a metal structurecapable of resisting heavy stresses without failure, and having suitablecharacteristics for use as pressure vessels even under such largepressures as are encountered, for instance, in gun barrels, or formachine members requiring also different characteristics of surfacemetal compared with that of the main body, as for example a shaft orpiston rod.

One manner of producing a metal article according to the presentinvention is to deposit metal by the arc process in successiveintersecting fusion beads along a non-adherent base, the bead depositsalso being superposed, if necessary, until the desired thicknessdimension is attained, the base being removed at a predetermined stageof the operation. Successive layers may be made from electrodes ofdifferent metals or compositions, and even one layer may be of differentmetal in different parts of its area.

If the deposit is simultaneously made from several electrodes, difierentcompositions may be selected for each for the purpose of forming anultimate alloy by solution of the one into the other to attain certainphysical characteristics in the metal of the finished article.

When a fusion layer is deposited upon a body of unfused metal, thesurface of'tlie latter is fused by the action of the deposited metaland, upon cooling, this fused surface stratum will shrink more than theunderlying metal and stresses will be set up so severe as to result incracks, or such as to make the resultant body less able to resistinternally imposed stresses than would otherwise be the case. When theintended use of an article is such as to be impaired by this feature,the unfavorable condition may be prevented by heating the unfused metalbody receiving the fusion layer to a sufliciently high temperaturewithout fusing it. The deposit as it is formed may be heated to withinthe plastic range so that after deposit of even large thicknesses therewill be no cracking after cooling, and the metal grain will be refined.The required heating of either the unfused metal body or the deposit maybe accomplished by electric induction, or resistance heating means.

If coated or covered weldrods or electrodes are used, means must beprovided for removing slag, if the coatings or coverings are slagforming. s

that the metal deposits are always made upon clean metal. The fusiondeposits may be formed under the protection of a fluxing material, or inthe presence of an inert or non-oxidizing blanket of gas, or undernormally solid blanketing substances of inert character.

It is also within the purview of the invention that the deposited metalbe forged before any substantial cooling, and a completed rough articlemay be worked or forged to final condition either after separate forgingof each layer or the forging may take place after the required thickness has been built up on successive strata. In this case a very finegrained and dense structure results, one that is capable of highstresses without failure.

The invention may involve the simultaneous use of a plurality ofweldrods the metals of which contribute to an ultimate alloy productsome particular characteristic, such as ductility, hardness, toughness,machineability or the like for all or a part of the thickness, or areadeposited. When desired, a part of the final body may be of a differentmetal, as for instance an outside face exposed to erosion may be oferosion resisting metal, or of corrosion resisting metal.

For the purpose of illustrating the invention, the following drawingsare referred to. In these drawings:

Fig. 1 is a side elevation, partly in section, of a set-up for acontinuous deposit of metal upon a mandrel and from one or moreweldrods;

Fig. 2 is an end elevation in section of th mandrel and deposit of Fig.1;

Fig. 3 is a diagrammatic view-illustrating the rolling of the stratafusion deposited on the mandrel shown in Fig. 1;

Fig. 4 is a transverse section of the mandrel and tube after rolling;

Fig. 5 is a longitudinal section of a completed tube; v

Fig. 6 is a transverse section of the tube of respectively, of onemanner of forming a bead deposit for a rod;

Fig. 12 is a perspective view indicating another manner of forming arod;

Fig. 13 is an end view of the rod strip removed from the base;

Fig. 14 indicates the manner of sizing and finishing the round rod:

Fig, 15 is an end elevation of the finished rod;

Figs. 16, 1'7, and 18 indicate stepsinthe forming of a flat plate;

Fig. 19 shows another step in a method of forming a fiat plate;

Fig. 20 shows a top plan view of the apparatus shown in Fig. 19; and

Fig. 21 is a diagrammatic view of the welding circuit of an apparatusfor carrying out the method of the present invention.

The apparatus indicated in Fig. 1 includes a bed plate I provided with abearing stand 2 in which is journaled the shank 3 of a rotating chuck dsupporting the mandrel 5. The chuck 6 is driven by means of a tailspindle 6 provided with gear 1 meshing with pinion 8 on one end of theshaft of a motor9, the other end of which carries a belt pulley i0. Abelt H over pulley ill drives pulley on the end of a shaft I3 operatinga suitable variable speed drive M. The latter transmits rotary motion toa lead screw I5 journaled'in bearings 16 and I! the axes of which areparallel to the axis of the chuck 1 and mandrel 5 carried thereby.

Traveling along the lead screw it are one or more arc welding heads itof a type which automatically advances theweldrod and controls thelength of are such, for instance, as is disclosed in the co-pendingapplication of James E. Train r, Ser. No. 730,852, filed June 16, 1934(now Patent 2,135,129, granted November 1, 1938). The Welding head mayfeed and regulate the arc of more than one weldrod, two, for instancebeing here shown at A and B.

. With the apparatus indicated in Fig. 1 operating in accordance withthe welding head and circuitdisclosure of the aforesaid Trainer patent,the rate of deposit from weldrods A and B may be controlled and the arcsbeing stabilized. The circuit of this apparatus not only includes theweldrod feeding motor or motors, but also the driving motor 9, and thusthe characteristics across the arcs control the rate of deposit, thespeed of the mandrel sand the feed of the lead screw 55, which lattermay, however, be independently yaried by changingthe position of thechange speed controller C. The control circuit will be hereinafterdescribed in greater detail.

With the apparatus as above described, and using a mandrel 5 of such acharacter the fusion deposited metal will not adhere, the weldrod metalfrom weldrods A and B is fused and deposited in intersecting oroverlapping helical formations along the mandrel 5, the weldrods beingmoved longitudinally of the mandrel 5 at a selected rate while themandrel 5 is rotated by the motor 9 at a selected and adjusted rate.There is thus produced upon the surface of mandrel 5 a tubular depositof helical beads, each successive bead laterally fused to the adjacentone that has been previously deposited. After a section of the mandrelhas been covered by such metallically continuous layer of weld metal,the mandrel is removed and transferred to a rolling mechanism of thetype used for rolling tubes over a piercing mandrel, such mechanismbeing indicated in Fig. 3 of the drawings. This mechanism includes rollsI8, which are four in number (only two being shown), pressure contactingthe unformed tube with their axes angled as indicated. .Th rollingoperation, 75

performed while the tube and mandrel are hot. produces a smooth exteriorwhile coincidentally expanding the metal of the tube so that the mandrelmay be .freely removed, thus leavinga finished tube IQ of weld metal ofuniform thickness.

The tube l9 thus formed may be given additional thickness, if desired,by mounting it upon an expanding mandrel 20 as shown in Fig. '7, thespindle 2| of which may be carried in the chuck 4 of the apparatus shownin Fig. 1, weldrods A and B being employed to produce an additionalfusion deposit while the tube is heated immediately in advanc of thepoint of deposit by an electric inductive heater or the like 22. Theheater is controlled so as to produce a forging temperature in the tubemetal, immediately in advance of the arc and over a narrowcircumferentialzone which is to be immediately overlaid with a depositof the fusion metal.

The external deposit is fused to the tube metal and, as the latterfreezes, the softness of the heated metal permits shrinkage withoutexcessive stress and \m'th no tendency to crack. If desired thisoperation may be repeated until the resulting product is of considerablethickness; in fact, various thicknesses may, be built up so that anarticle may be thicker at one end than at the other. as shown in Fig. 9,this be ng accomplishedby varying the length over which posits are laid.

Any'of ,the successive layers may be of metal different. than the othersby changing the weldrods, and also any of the layers may be of an alloyof two or more metals determined by using weldrods of ap ropriatelydifierent metals to form the desired alloy.

Ii desirable there may be substituted for the mandrel 5 of Fig. 1 atubular mandrel upon which the deposits are made, this mandrel beingsimilar to that indicated in Fig. 7 andbeing heated inductively in thesame manner as shown in Fig. 7 so'that shrinkage is taken care of as themetal freezes. Alternatively, the tube may be slotted longitudinally orspirally, to take care of the scope of this invention to roll the tubeas in- Fig. 3 between the stages of depositing successive layers, andthat if coated weldrods are used which are of a slag forming characterall the slag left after the deposit of one layer shall be removed beforethe deposit of the next layer.

The invention contemplates also the making of a shaft in the mannerindicated in Figs. 10 to 15, y

In this case the weldrod A deposits inclusive.

- a strip of fusion metal 23 on a non-adherent base 26 having a fiatface, as shown in Fig. 11, or hav- "value.

ing a grooved face as shown in Fig. 12 at 25, and

from which face the strip 23 built to the predetermined thickness issubsequently removed.

The rough strip is then fed through a heater, indicated herein as of theelectricinduction type as at 28, which raises the temperature to forgingThe strip then passes'to the co-acting rolls 2?! and 28 for reducing thesection and producing a rod of the desired cross section.

This rod of weld deposited .metal is then mounted in the apparatus ofFig. 1 to receive successive layers of weld metal in the mannersuccessive depreviously described. During the course of the formation ofthe shaft there may be re-rolling at intervals, each layer being fusionattached to the core while the latter is at a temperature, in theforging range.

When the final shape is to resist rubbing wear on its outer surface oneor more of the final layers may be deposited from weldrod metals thathave become hard. The final finishing operation of the shaft may be byfinal rolling followed by machining or grinding to the desired surfacesmoothness and the required dimensions.

Another illustrative method of making a plate of weld metal isdiagrammatically illustrated in Figs. 16 to 20, inclusive, wherein thereis indicated the fusion depositing of a strip 30 on a .plate ofnon-adherent material 3I followed by the deposition of parallel stripsfusion welded to those previously laid to form a wide strip, such asshown in Fig. 18. This may be accomplished by the simultaneous fusion ofa number of weldrods arranged side by side. The strip thus formed isthen removed from its original base. The strip is then placed upon atable 32 as shown in Fig. 19 and fed over a source of heat risingthrough a slot 33 to raise the strip to a forging temperature prior tothe deposition of an additional layer of metal. The latter may beapplied by successive weldrods A, .3 arranged across the face of thestrip as shown in Fig. 20, with each successive weldrod oflset asindicated so as to permit the deposits from the various weldrods toproperly join. After the deposit of successive strata in this manner theresulting sheet or strip may be rolled between fiat rolls, forged orotherwise manipulated to produce a plate of the desired size andthickness. It is, 01' course, understood that successive layers, as inthe case of a tube, may be of different metals, or that the weldrods maybe regulated so as to produce a desired alloy either throughout theplate, or a varying alloy through the thickness of the plate in order togive the final product the desired properties.

The welding machine described in connection with Fig. 1 is used with awelding headand circuit'of the type of weldrod feed and control of theaforesaid Trainer patent, but modified in accordance with the diagramherein shown by the inclusion in the circuit of a control motor 9 fordriving the mandrel 5.

its speed increased as the arc returns to normal, or the motor 9 mayhave a normal rate of speed divided into two steps.

The work is indicated, for instance, as mandrel 5, and the weldrod at Z,the contact faces 300 of the weldrod being engaged by thediagrammatically represented current carrying shoes 30I. The weldrod Zis moved to or from the work by a reversible motor IN.

A jet of inert gas or reducing gas may be fed in proximity to the arcthrough a nozzle I55 from a supply pipe I53, controlled by a valve I56which may be manually operated or automatically operated by the solenoidI51.

The arc circuit includes a power supply, preferably alternating currentat a suitable voltage, for example 220 volts, which is connected to theprimary of a welding transformer I59 and adjustable reactor I60. Oneside of the secondary of the transformer and reactor is connected by alead I6I to one pole I62 of a magnetically operated switch (D), theother pole I64 of which is connected to the current carrying shoes 30IThe motor 9 may have its speed reduced as the arc lengthens, and haveengaging the weldrod Z. The other side of the transformer connects by alead I65 to the work 5; thus when the switch (D) is closed an arc may bestruck and held between the end of the weldrod and the work 5.

After the arc is started, it may be controlled by regulating the rate offeed of the weldrod through control of the speed of the reversibleweldrod feed motor Ill.

In order to effect control of the reversible weldrod feed motor H4, inthe form of the invention illustrated, a direct current supply line at asuitable voltage, for example 60 volts, is provided. As shown, thedirect current supply line includes leads I66 and I61; and, as willpresently appear, there is obtained an automatic regulation of the arethrough the medium of control apparatus energized by this direct currentsupply and control apparatus actuated by the changing characteristics ofthe arc.

With the circuit shown, the operator adjusts the weldrod I5I to the work5 and closes the start-stop switch to establish connection between thecontacts I63 and I69. Current then flows from the lead I61, through thecontacts I63 and I63, to the solenoid which operates the switch (A),thence back to the other side I66 of the supply line. Switch (A) willthen close to establish a flow of current therethrough from the side I61of the supply line, through thesoleflow through the solenoid whichoperates an arc control relay switch (F) having a core or plunger I63.The latter operates two sets of contacts I10, HI and I12, I13,respectively. When the solenoid of switch (F) is energized core I63thereof is moved upward to first establish connection between contactsI10, HI and after this contact is made further movement of the corebreaks the connection between contacts I12, I13.

The core of the switch (F) is urged downward- ,ly by a suitable springI14. The engagement of the contacts I10 and "I of the arc control relayswitch (F), causes current to flow from the conductor I61 through thesolenoid for operating the switch (B) and back to the conductor I66,thereby operating the switch to cause the engagement of contacts 200,20I and 202, 203 to permit current flow through motor H4 in a directionto feed the weldrod I 5| toward the work, the field noid to close theswitch. The solenoid is designed to overcome the force of the spring 201when the voltage flowing therethrough exceeds a predetermined amount,for example 50 volts. A resistor I18 of predetermined characteristics,for example, 20 ohms is arranged in shuntrelation with contacts 208 and209 of switch (E), and

both are in series with the circuit which includes the solenoid ofswitch (F), the purpose of such arrangement being to provide for theprotection of the solenoid of switch (F) before the arc is struck or incase the voltage becomes excessively high due to a long arc or failureof the are. With the striking of the arc, the voltage drops and spring201 closes switch (E), thereby shunting the resistor I18.

With the foregoing arrangement, should the arc lengthen and cause anincrease in voltage through the solenoid of the arc control relay switch(F), such solenoid will move the relay plunger Q63 upward to a pointwhere the eneasement of contacts I12 and I13 is broken while contacts Iand HI remain in engagement, and as a result current flows through ashunt circuit including a manually adjustable rheostat I11 arranged inseries with the field of the motor II4. This action causes this motor toincrease its speed and thereby move the end of the weldrod ,nearer thework at an increased rate, thus The speed at which the motor I operateswhen the connection between contacts I12 and I13 is broken, depends uponthe previously selected adjustment of the rheostat I11. Also, the arclength control rheostat I18 in series with the solenoid of switch (F) isadjustable to absorb more or less of the arc voltage so as to alter thecritical arc voltage at which solenoid of switch (F) breaks theconnection between contacts I12 and I13. Therefore, the rheostat I18functions to determine the arc length at which stable operation. ismaintained.

Should the weldrod ireeze to the work 5, the resistance to flow drops tozero, thus short circuiting th solenoid of the arc control relay switch(F). As a result spring I14 disengages contacts I10, "I and de-energizesthe solenoid of switch (B). A spring 2! will then break the connectionbetween contacts 200,, 20I and 202, 203, and establish connectionbetween contacts 20I, 204, and 203, 205, thereby causing.

I'll to be re-engaged, energizing the solenoid of switch (B), andcausing the latter to again close contacts 200, 20l and contacts 202,203, and the current to flow throughthe motor I I4 in a direction tomove the weldrod toward the work.

In connection with this circuit it is to be noted that during the fusiondeposition of the weldrod metal, the contacts. I10, I 1I of the arccontrol relay switch (F) are closed at all times except when theresistance to current flow set up by the gap approaches zero by,forinstance, the short circuit condition above described. However, theright hand contacts I12, I13 of the switch (F) open and close accordingto slight adjustment oi the relay plunger responding to variations inthe voltage due to variations. of arc length. It will thus be evidentthat the contacts 612, I13 of the arc control relay switch (F) place theweldrod field rheostat I11 in and out of the circuit-oi the field of themotor H4, and with this arrangement the weldrod feed motor is caused tooperate at a predetermined high speed, or a predetermined slow'ratedepending upon the relationship of contacts I12, I13.

The predetermined high speed of the weldrod feeding motor II4 must besuch that the weldrod or electrode is fed to the work at a rate fasterthan it is consumed by the arc. Otherwise the operation of the arc wouldbe unstable. However, the predetermined slow rate is preferably slowerthan the rate of consumption of the weldrod by the arc, as otherwise thearc will continue to shorten, thereby causing the plunger of the arccontrol relay switch (F) to drop, opening the contacts I12, I13 andde-energizing the coil of switch (B) which would cause the weldrodfeeding motor II4 to reverse.

The motor 9 as shown in Fig. 21 is connected for unidirectional rotationat selected speeds, according to the amount of resistance in series withthe shunt field winding. For normal conditions of the arc, the motorrotates at maximum speed, while for abnormal conditions such aslengthening of the are or short circuit with the work, the speed ,of themotor is reduced, or the motor stopped altogether, as will behereinafter set forth.

An additional contact I12 is included in the relay switch (F) so thatwhen the arc lengthens and the connection between contacts I12 and I13is broken, a contact is immediately established between I13 and-thelower contact I12 which short circuits the resistance (R) in the shuntfield of motor 9; thus with an increased speed of the feed motor II4 toshorten the arc,

the speed of motor 9 is reduced since during this period the weldrodmetal is being deposited at a When the arc is restored to normal length,and voltage across the relay (F) is lowered, the spring I14 acts tobreakthe connection I13, I12 and reestablishes'connection between I13and the upper contact I12.

In order that the motor 9 shall operate only when the arc is normal, therelay (G) is provided to close and open the power supply to motor 9.When the arc is initiated and deposition of weld metal begins, relay (F)is energized and contacts I10 and HI are connected, as alreadydescribed.

' work.

When the arc voltage drops below the requiredminimum for normaloperation due, for example, to-the weldrod contacting the work, thecontacts I10, "I are opened and switch (G) is de-energized, therebyopening the power lead to motor 9 and'stOPping movement of the work,while the feed motor is reversed to reestablish the normal arcingdistance.

It will be evident from the foregoing that the apparatus described isadapted to carry into effect the illustrative method, and while specificdetails are herein given it is nevertheless to be understood that inpracticing the invention I may resort to any modifications fallingwithin the scope of the appended claims.

This application is a division of my previous application 224,022, filedon August 10, 1938.

' What is claimed is:

1. In a method particularly adapted for the manufactured tubularproducts, utilizing a fusion welding process to deposit metal from aweldrod or wire upon'a base to form a central element of the ultimateproduct, separating the deposited metal and the base, heating saidcentral element in annular circumscribin'g zones progressing therealong,and immediately following up the progressive heating with similarlyprogressing electric fusion deposition upon said member of additionalmetal derived from a weldrod, said deposition taking place before theheated metal has cooled to any substantial degree and involvingintersecting convolutions of weld metal deposited as a helix enclosingand integrally bonded to said element.

2. In a method particularly adapted for the manufacture of a tubularmember, utilizing the electric fusion welding process to deposit metalfrom a weldrod or wire upon a cylindrical base to form a central elementof the ultimate product, separating the deposited metal and the base,heating said central element in circumscribing zones progressing fromone end thereof, and following up the progressive heating with similarlyprogressing electric fusion deposition upon said member of additionalmetal derived from a weldrod, said deposition taking place before theheated metal has cooled to any substantial degree, and involvingintersecting convolutions of weld deposits made as a helix enclosing andintegrally bonded to said member.

3. In a method particularly adapted for the manufacture of tubularmembers such as sun barrels of large calibre, utilizing the electricfusion welding process to deposit metal from a weldrod upon a base toform the central element of the gun barrel, separating the depositedmetal and the base, removing the slag coating resulting from saidprocess, heating the formed metal member in circumscribing zonesprogressing from one end thereof, and following up the progressiveheating with similarly progressing electric fusion deposition upon saidelement of additional metal derived from a weldrod or wire, saiddeposition taking place before the heated metal has cooled below theplastic range and involving intersecting convolutions of weld depositsmade as a helix enclosing and integrally bonded to said element.

4. In a method of forming a tubular member, utilizing an electric fusionwelding process to form contiguous convolutions of intersecting welddeposits made as a helix enclosing a non-adherent base and forming aninner element of said member, said deposits being derived from a coatedweldrod or wire which is automatically fed toward said base member,separating the base and any extra deposited material from the depositedmetal, zone heating the deposited metal by electric induction heatingeffecting relative movement between the heating zone and the depositedmetal, following up said zone heating with the similar electric fusiondeposition upon said inner element of additional metal, and socoordinating said heating and the second deposition of metal that thelatter takes place upon the first deposited metal while the latter is ata relatively high temperature.

Isaac mama.

